"Mozilla and the Xiph.Org Foundation are pleased to announce the Internet Engineering Task Force (IETF) has standardized Opus as RFC 6716. Opus is the first state-of-the-art, fully Free and Open audio codec ratified by a major standards organization."

Essentially, little changed except removal of the -voice and -music modes which weren't useful and other things that simply made building the binary easier, AFAICT.

Recent versions including the free reference implementation have all been tuned to a very good performance, though moderate improvements on music and probably problem sample performance will doubtless be made over time. The days of naive reference encoders (like early mp3 encoders) seem to have passed.